NEUROFIBRILS 493 



four hours ; wash quickly ; stain in ammoniacal silver nitrate 

 solution diluted to 40 c.c. for thirty minutes. Wash, reduce, 

 tone, and mount as usual. 



Mod. 4. Place sections in 50 per cent, pyridine for six to 

 eighteen hours ; wash in re-distilled water for twenty-four to 

 forty-eight hours ; 2 per cent, silver nitrate at 37° C. for twenty- 

 four hours, etc., as in Mod. 3, 



Mod. 5. Place sections in pure pyridine for four to twelve 

 hours. Wash in re-distilled water overnight. Transfer sections 

 into 20 per cent, formalin prepared with re-distilled water for 

 about twenty-four hours. Wash again in re-distilled water over- 

 night ; 2 per cent, silver nitrate at 37° C, etc., as before. 



Mod. 6. Sections are treated first with 20 per cent, formalin, 

 and then with pure pyridine, in the reverse order of Mod. 5. 



Mods. 7 and 8. The same as Mods. 5 and 6, but replacing the 

 pyridine with a mixture of 3 j^arts of methyl alcohol and 2 parts 

 of water. 



Mod. 9. Place sections in a mixture of equal parts of 20 per 

 cent, formalin and methyl alcohol for twenty-four hours ; wash 

 in re-distilled water for six to twenty-four hours ; 2 per cent, 

 silver nitrate at 37° C. for twenty-four hours, etc., as before. 



Mod. 10. Place sections into 20 per cent, formalin for twenty- 

 four hours, transfer them, without washing, into a mixture of 

 equal parts of 20 per cent, formalin and methyl alcohol, etc., as 

 in Mod. 9. 



Mod. 3 is particularly suitable for human material of young 

 individuals : Mod. 4 for adult subjects. Mods. 5 and 6 are usefid 

 for the study of neurofibrils in the various elements of the cortex 

 cerebelli and for the staining of the granules. Mods. 7, 8 and 9 

 are to be preferred for the demonstration of pericellular baskets 

 and nervous processes. Mod. 10 gives very complete stainings, and 

 is the most certain of all ; preparations are, however, fairly dark 

 and, therefore, more suitable for general view. 



1024. Neurofibrils ; Other Methods. Cox's Method for fibrils of 

 spinal ganglion cells ; see Ztschr. iviss. Mikr., xiii, 1896, p. 498, and 

 Anat. Hefte, x, 1898, p. 98. 



S. Meyer's Berlin blue, see Anot. Anz., xx, 1902, p. 535. 



LuGARo's collargol (colloidal silver) method, see Monit. Zool. Ital., 

 XV, 1904, p. 353. 



JoRis' colloidal gold method has not been received with favour ; see 

 Bull. R. Acad. Med. Belg., xviii (S. iv), 1904, p. 293. 



Sand (C. R. Ass. Anat. Bruxeltcs, 1910 ; Bibliogr. Anat. Supp., 

 1910, p. 128, or Ztschr. iviss. Mikr., xxviii, 1911, p. .500) gives the fol- 

 lowing as entirely certain for man, (l')g, cat, and rabbit. Specimens of 

 not more than 5 mm. in thickness are fixed for forty-eight hours in a 

 freshly-prepared mixture of 90 parts of acetone and 10 of nitric acid, 

 to be changed for fresh after half an hour, and once again Avithin 

 twenty-four hours. Wash out for at least six hours in pure acetone, 

 changed two or three times. INIake paraflin sections and bring them 



